While Britain has escaped relatively unscathed, there is still the potential for protests against the film to become controversial in themselves.

In 2006, a protest against a Danish newspaper which published cartoons of the Prophet Mohammed saw demonstrators carry placards calling for those who insulted the figurehead to be killed.

The demo prompted a change in the law to allow prosecutions of those holding the placards, in a move which discomforted civil liberties advocates.

Campaigners' demands for a law against "abuse" of religion is not unthinkable. New Labour tried to get a law banning the hatred of religion onto the statute book but that section of the racial and religious hatred bill was voted down by MPs.